1. Field of the Invention
The present invention relates to a power seat apparatus, and more particularly to a power seat apparatus in which a seat-cushion may be movable in the horizontal direction and/or in the vertical direction of a vehicle body.
2. Description of the Prior Art
A conventional power seat apparatus of the type, which is shown in Japanese Patent Laid-Open Print No. 58-97528, published without examination on Jul. 10, 1983, includes lower rail means fixedly mounted on a floor of a vehicle body, upper rail means slidably mounted on the lower rail means, a first mechanism provided at a front portion of the upper rail means for lifting or lowering a front portion of a seat-cushion, a second mechanism provided at a rear portion of the upper rail means for lifting or lowering a rear portion of the seat-cushion and a third mechanism provided at a portion of the upper rail means for moving the upper rail means along the lower rail means. In the conventional power seat apparatus, when the rotational torque is transmitted to the first mechanism, the second mechanism and the third mechanism through a first shaft, a second shaft and a third shaft, the front portion of the seat-cushion is moved vertically, the rear portion of the seat-cushion is moved vertically and the seat-cushion itself is moved in the horizontal direction of the vehicle body, respectively.
The first shaft is connected to a first gear which is driven by a reversible motor via a first solenoid clutch, the second shaft is connected to a second gear which is meshed with the first gear via a second solenoid clutch and the third shaft is connected to a third gear which is meshed with the second gear via a third solenoid clutch. For transmitting the rotational torque from the motor to any one of shafts, the corresponding solenoid clutch has to be actuated, which results in noise emittance. Furthermore, since each shaft has to be provided with corresponding gears, the whole construction of the power seat becomes complex.